Monday, 6 February 2012

2.86 Eyes

Our eyes is the body's receptor to light and gives us the sense of sight, which most of us depend upon. It detects changes in light intensities.

At the front of the eye is the cornea where the light enters the eyes. The light then passes through the pupil which is surrounded by the coloured iris. The light focuses on the fovea and the optic nerve receives the image perceived and projects it our brains.

Parts - Functions

Cornea - allows light in and is the main refractive surface of the eye

Pupil - The pupil either dilates or contracts with the help of the iris. This controls the amount of light entering the eye so that the lens doesn't get damaged.

Iris - Muscle surrounding the pupil which helps in dilating and making the pupil smaller. The logitudinal muscles contract and the radial muscles relax to make he pupil big and vice versa.

Lens - Helps with the refraction of the light onto the retina.

Optic Nerve - Carries impulses generated by the retina to the brain and turns into vision.